Drill guide



R. H. MELTON Jan. 2, 1968 DRILL GUIDE 2 Sheets-Sheet l Filed Oct. 22,1965 INVENTOR Roe/59T HMB/ To N BY M X' FW...

United States Patent O 3,361,493 DRILL GUIDE Robert H. Melton, 605Camellia Drive, Lafayette, La. 70501 Filed Oct. 22, 1965, Ser. No.501,753 2 Claims. (Cl. 308-4) ABSTRACT OF THE DISCLOSURE A drill guideattached to and made a part of a drilling string for centralizing adrill bit and collar assembly in a bore hole, including a bore wallengaging sleeve in which a part of the drilling string is journaled andanti-friction bearing means rotatably connecting the sleeve to said partof the drilling string and combining therewith to form passages for theiiow of drilling uid between said part and the sleeve.

This invention relates to a drill guide which is attached to and made apart of a drilling string for centralizing a drill bit and drill collarassembly in a bore hole to maintain the drill bit directed toward apredetermined target during the drilling operation.

More particularly, it is an aim of the invention to provide a drillguide including a sleeve which is maintained substantially stationary byfrictional engagement with the wall -of a bore hole and in which a bodymember, forming a part of the drilling string, is disposed for rotationand is maintained in a position axially of said sleeve.

A further object of the invention is to provide a drill guide providingpassages for the ow of drilling fluid therethrough.

Another object of the invention is to provide a drill guide whichreduces the torque normally caused by a drill string rubbing on the wallof the bore hole.

Various other objects and advantages of the invention will hereinafterbecome more fully apparent from the following description of thedrawings, illustrating a presently preferred embodiment thereof, andwherein:

FIGURE 1 is a side elevational View of the drill guide;

FIGURE 2 is a cross sectional view thereof taken substantially along aplane as indicated by the line 2 2 of FIGURE l;

FIGURE 3 is a longitudinal sectional view taken substantially along aplane as indicated by the line 3 3 of FIGURE l;

FIGURE 4 is a cross sectional view taken substantially along a plane asindicated by the line 4 4 of FIGURE 1;

FIGURE 5 is an enlarged fragmentary longitudinal sectional View, takensubstantially along a plane as indicated by the line 5 5 of FIGURE l,and

FIGURE 6 is an enlarged fragmentary longitudinal sectional view takensubstantially along a plane as indicated by the line 6 -6 of FIGURE 4.

Referring more specifically to the drawings, the drill guide in itsentirety is designated generally S and includes an elongate rigid bodymember 9 of circular cross section having a centrally disposed bore 10extending longitudinally therethrough. The body 9 is provided with fourlongitudinally extending circumferentially spaced grooves 11 foraccommodating inner portions of four corresponding ribs 12 which may 'besecured to the body 9 in any conventional manner, with inner portionsthereof conformably fitting in the grooves 11, as seen in FIGURES 3 and4. Ribs 12 have substantially flat outer faces 13 which are equallyspaced from the longitudinal center of the body 9 and which preferablyterminate in beveled ends 14.

Each rib 12 is provided with six corresponding sockets 15 which openthrough the outer face 13 thereof. Each socket 15 has parallel sidewalls 16, as seen in FIGURE Patented Jan. 2, 1968 ICC 4, and paralleltop and bottom walls 17, as seen in FIG- URE 6, which are disposed atright angles to the side walls 16, as seen in dotted lines in FIGURE 1.Each socket 15 has a rear Wall 18 which is disposed parallel to theouter face 13 of the rib. Each of the sockets 15 of each of the ribs 12contains a steel ball bearing 19 which is of a diameter less than thespacing between the socket Walls 16 -or the socket walls 17. Each ballbearing 19 has a diameter greater than the depth of the socket 15 and aradius less than the depth of said socket, so that less than one-half ofthe ball bearing protrudes from the socket when the ball bearing isabutting the rear wall 18, as seen in FIGURE 6.

A rigid sleeve 20 of cylindrical cross section has an inner wall face 21of a diameter somewhat greater than the spacing between the outer faces13 of two oppositely disposed ribs 12, as clearly illustrated in FIGURES2, 3 and 4. The sleeve 20 has a smooth outer face 22 which is providedwith beveled ends 23, and said sleeve is of a length less than thelength of the ribs 12. The sleeve 20 is provided with six annularinternal grooves 24 which open through its inner face 20 and which arespaced apart distances corresponding to the spacing between the sockets15 of each rib 12. The grooves 24 are of a width correspending to thespacing between the top and bottom walls 17 of each socket 15. The innerdiameter of the sleeve 20 and the depth of the grooves 24 are Such thatthe ball 'bearings 19 protrude into said grooves to support the sleeve210 concentrically around the body 9. It will be noted that each groove24 is engaged by four ball bearings 19, one contained in the socket 15of each rib 12, and said sockets and grooves form ball bearing races,and, in combination with said ball bearings, constitute anti-frictionbearing means for mounting the sleeve concentrically on the body 9.

The sleeve 20 is provided with threaded openings 25 one of which opensinto each of the grooves 24 and which openings are normally closed bythreaded plugs 26. The openings 25 and plugs 26 are staggered relativeto one another, as seen in FIGURE l. The openings 25 are of a diametercorresponding to the width of the grooves, as seen in FIGURE 2, so thatwhen the plugs 26 are removed, ball bearings 19 can `be applied to thesockets 15 through said openings when the openings are in alignment withthe sockets. It is for this reason that the openings are staggered, sothat only a single opening will be in alignment with the socket in anyposition of rotation of the sleeve 22 on the body 9. The inner ends ofthe plugs 26 are shaped to conform to the shape of the beds of thegrooves 24 and are disposed ush therewith, as seen in FIGURE 5, so thatthe ball bearings 19 can roll unobstructed across the inner ends of saidplugs.

The body 9 is interposed in and forms a part or section of an otherwiseconventional drill string, not shown. The smooth outer surface 22 of thesleeve 20 is adapted t-o engage the wall of a bore hole, not shown, tomaintain the body member 9 and the drill string, of which it .forms apart, centered in the bore hole. The smooth outer surface 22 of thesleeve enables the sleeve to slide readily longitudinally of the borehole either as the drill string is being advanced downwardly therein oras being withdrawn therefrom. However, said outer surface 22frictionally engages the wall of the bore hole to remain substantiallystationary, with respect to rotational motion, as the body member 9rotates about its longitudinal axis with the drill string, so that thesleeve 20 forms a guide in which the body member 9 revolves and by whichit is maintained centered with respect to said sleeve -by theanti-friction bearing means 15, 19, 24 and which anti-friction bearingmeans additionally functions to support the sleeve on the body member 9.

The ribs 12 combine with the sleeve 20 to form four passages 27, as seenin FIGURES 2 and 4, through which drilling fluid may pass between thebody member 9 and sleeve 20 and longitudinally thereof.

A drill string may be provided with any number of drill guides 8,depending upon the length thereof.

It will be readily apparent that the body 9 could be provided with threeinstead of four ribs 12 and with any number greater than four, if sodesired.

Various other modications and changes are contemplated and may beresorted to without vdeparting' from the function or scope of theinvention `as hereinafter defined by the appended claims.

I claim as my invention:

A drill guide comprising an elongated rigid body member forming a drillstring section, a cylindrical guide sleeve having an outer bore wallengaging surface, antifriction bearing means rotatably mounting thesleeve on the 'body member and providing means journaling the bodymember to rotate in and be guided by the sleeve, said body member beingprovided with at least three longitudinally extending circumferentiallyspaced ribs protruding outwardly therefrom and around which the sleeveis disposed, each rib having longitudinally spaced outwardly openingsockets, said sleeve having inwardly opening annular grooves with whichthe sockets are aligned, and ball bearings confined in said sockets andgrooves and rotatably connecting the sleeve to the body member, saidsockets, grooves and ball bearings constituting said antifrictionbearing means.

2. A drill guide comprising an elongated rigid body member forming adrill string section, a cylindrical guide sleeve having an outer borewall engaging surface, antifriction `bearing means rotatably mountingthe sleeve on the body member and providing means journaling the bodymember to rotate in and be guided by the sleeve, said body member havinglongitudinally extending ribs protruding outwardly therefrom andprovided with sockets forming bearing races of said anti-frictionbearing means and around which the sleeve is disposed concentrically ofthe body member, said ribs combining with the body member and sleeve toprovide circumferentially spaced longitudinal drilling uid passagestherebetween opening beyond the ends of the sleeve.

References Cited UNITED STATES PATENTS 1,112,946 10/1914 Turnbull 308-61,756,195 4/1930 Holdaway 308-6 2,248,160 7/1941 Crawford 308-42,601,473 6/1952 Weir 308-6 FOREIGN PATENTS 307,212 2/1929 GreatBritain.

MARTIN P. SCHWADRON, Primary Examiner.

L. L. .TOI-INSON, Assistant Examiner.

